DEMO MANUAL DC1744A
LT3799
Offline Isolated Flyback
LED Driver with PFC
Description
Demonstration circuit 1744A is an off-line isolated flyback
converter featuring the LT
®
3799. The demo board is de-
signed to drive a single LED from an input voltage range
of 90V AC to 270V AC. It is also designed to comply with
IEC 61000-3-2 Class C harmonics standard and EN55015B
conducted EMI standard.
The LT3799 controls an isolated flyback converter in
boundary mode, suitable for LED applications requiring
4W to over 100W of LED power. Its novel current sensing
scheme delivers a well-regulated output current to the
secondary side without using an opto-coupler. Its unique
bleeder circuit makes the LED driver compatible with
TRIAC dimmers without additional components. Open-
and shorted-LED protection ensures long-term reliability.
The LT3799 is available in a low profile, thermally-enhanced
16-lead MSOP package.
The LT3799 data sheet gives a complete description of
the part, operation and application information. The data
sheet must be read in conjunction with this quick start
guide for demo circuit 1744A.
Design files for this circuit board are available at
http://www.linear.com/demo.
L,
LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear
Technology Corporation. All other trademarks are the property of their respective owners.
perForMAnce sUMMArY
PARAMETER
Input Range
Output Current I
OUT
Maximum Output Voltage
Minimum Output Voltage
(T
A
= 25°C)
VALUE (TYPICAL)
90V AC to 270V AC
1.07A
5V
3V
CONDITIONS
Line Frequency, 50Hz/60Hz
V
IN
= 120V AC, V
LED
= 3.6V
dc1744afa
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DEMO MANUAL DC1744A
qUick stArt proceDUre
IMPORTANT NOTE TO CUSTOMERS:
HIGH VOLTAGES ARE PRESENTED ON THE DEMO CIR-
CUIT, AND CAN LEAD TO LETHAL INJURIES TO HUMAN
BODY. ONLY QUALIFIED PERSONNEL SHOULD OPERATE
IT. IT IS STRONGLY RECOMMENDED TO USE SAFETY
GLASSES AND AN ISOLATION TRANSFORMER.
NOTE. IMPROPER COMPONENTS REPLACEMENT ON
THE DEMO CIRCUIT CAN CAUSE PERFORMANCE DE-
TERIORATIONS, CIRCUIT MALFUNCTION, PROPERTY
DAMAGE, AND EVEN LIFE-THREATHENING INJURIES.
CONTACT LINEAR TECHNOLOGY APPLICATIONS EN-
GINEERS FOR PROPER COMPONENT REPLACEMENT.
Demonstration circuit 1744A is easy to set up to evalu-
ate the performance of the LT3799. Refer to Figure 1 for
proper measurement equipment setup and follow the
procedure below:
1. Connect a 1A LED between LED
+
and LED
–
terminals.
2. With power off, connect the input power supply to Line
(L) Input and Neutral (N) Input.
3. Turn on the power at the input.
NOTE: Make sure that the input voltage does not exceed
the maximum input voltage (270V AC).
4. Check for the proper output current.
Once the proper output currents are established, adjust
the input voltage and/or the load and observe the output
current regulation, efficiency, power factor and other
parameters.
~
A
AC
POWER SUPPLY
90V AC TO 270V AC
~
~
V
+
A
–
+
V
–
Figure 1. Proper Measurement Equipment Setup
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DEMO MANUAL DC1744A
qUick stArt proceDUre
1.2
1.0
0.8
I
LED
(A)
0.6
0.4
0.2
0
0
30
60
90
120
TRIAC ANGLE (DEG)
150
180
DC1744 F02
Figure 2. LED Current vs TRIAC Angle (120V AC Application)
0.99
0.97
POWER FACTOR
0.95
0.93
0.91
0.89
0.87
0.85
90 110 130 150 170 190 210 230 250 270
V
IN
(VAC – RMS)
DC1744A F03
Figure 3. Power Factor vs Input Voltage
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DEMO MANUAL DC1744A
pArts list
ITEM
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
Hardware
2
E4, E5
TURRET
MILL-MAX 2308-2-00-80-00-00-07-0
QTY
1
1
1
1
1
1
1
1
1
1
1
1
1
2
1
1
3
1
2
1
2
1
1
1
1
2
1
2
1
1
1
1
1
1
REFERENCE
B1
C1
C2
C3
C4
C6
C7
C8
C13
C20
C21
C22
D1
D2, D8
D7
D9
L1, L2, L3
Q1
R1, R5
R2
R3, R18
R4
R8
R9
R10
R11, R16
R12
R17, R24
R19
R20
R30
R32
T1
U1
PART DESCRIPTION
RECTIFIER, BRIDGE 600V 0.8A
CAP 33nF 20% 310V AC MKP
,
CAP 1812 22nF 5% 630V C0G
,
CAP 1210 10µF 20% 50V X7S
,
CAP 68nF 10% 450V RADIAL
,
CAP 0603 0.1µF 10% 16V X7R
,
CAP 0603 68nF 10% 50V X7R
,
CAP 0805 4.7µF 10% 25V X5R
,
CAP 0805 2.2nF 10% 250V U2J
,
CAP 2.2nF 10% 550VAC TYPE “Y1”
,
CAP 0603 4.7pF ±0.25pF 50V NP0
,
CAP 1500µF 20% 6.3V ELEC
,
DIODE, ULTRA FAST RECOVERY RECTIFIER
DIODE, FAST SWITCHING
DIODE, SCHOTTKY BARRIER RECTIFIER
DIODE, ZENER 33V
IND, 3.3mH, SMD
XSTR, MOSFET, N-CHANNEL 600V
RES, 1206 100k 5% 1/4W
RES, 0805 200k 5% 1/8W
RES, 0603 100k 1% 1/10W
RES, 0603 4.99k 1% 1/10W
RES, 1206 300mΩ 1% 1/4W
RES, 0603 20Ω 5% 1/10W
RES, 1210 100Ω 5% 1/4W
RES, 1206 499k 1% 1/4W
RES, 0603 3.48k 1% 1/10W
RES, 0805 10k 5% 1/8W
RES, 0603 40.2k 1% 1/10W
RES, 0603 24.9k 1% 1/10W
RES, 1210 750Ω 5% 1/2W
RES, 0603 10k 5% 1/10W
XFMR, FLYBACK (T201)
IC, TRIAC DIMMABLE OFFLINE LED DRIVER
MANUFACTURER/PART NUMBER
DIODES INC. HD06-T
VISHAY BFC233920333
TDK C4532C0G2J223J
TAIYO YUDEN UMK325C7106MM-T
RUBYCON 450MMK683K
MURATA GRM188R71C104KA01D
AVX 06035C682KAT2A
TDK C2012X5R1E475K
MURATA GRM21A7U2E222JW31D
VISHAY 440LD22-R
AVX 06035A4R7CAT2A
SANYO 6SEPC1500M+T
CENTRAL SEMI CMMR1U-06 TR
DIODES/ZETEX BAV20W-7-F
CENTRAL SEMI CMSH2-40L TR13
DIODES INC SMAZ33-13-F
COILCRAFT LPS6235-335ML
INFINEON SPU04N60C3
VISHAY CRCW1206100KJNEA
VISHAY CRCW0805200KJNEA
VISHAY CRCW0603100KFKEA
VISHAY CRCW06034K99FKEA
VISHAY RCWE1206R300FKEA
VISHAY CRCW060320R0JNEA
VISHAY CRCW1210100R0JNEA
VISHAY CRCW1206499KFKEA
VISHAY CRCW06033K48FKEA
VISHAY CRCW080510K0JNEA
NIC NRC06F4022TRF
VISHAY CRCW060324K9FKEA
VISHAY CRCW1210750RJNEA
NIC NRC06J103TRF
WURTH ELEKTRONIK 750813002
LINEAR TECH. LT3799EMSE
Required Circuit Components
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DEMO MANUAL DC1744A
scheMAtic DiAgrAM
dc1744afa
Information furnished by Linear Technology Corporation is believed to be accurate and reliable.
However, no responsibility is assumed for its use. Linear Technology Corporation makes no representa-
tion that the interconnection of its circuits as described herein will not infringe on existing patent rights.
5
Analog electronics
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